Theron, 39, worked with an adoption agency for six months before adopting the African-American girl in July.

August joins big brother Jackson, 3, who Theron adopted from her native South Africa in 2012.

Being a mom comes naturally for Theron, who knew she wanted to adopt from an early age. Last year, the Oscar winner reminisced to Vogue about a letter she wrote when she was 8 that read, "What I want for Christmas this year is for you to take me to the orphanage so that we can adopt a brother or a sister."